Display unit and its manufacturing method

ABSTRACT

A display unit which can realize reduction in thickness and weight of the display unit by omitting a void between a touch panel and a display panel, and its manufacturing method. Whole faces of the touch panel and the display panel are directly bonded together with an adhesive layer in between. The display panel has a structure wherein a driving substrate in which organic light emitting devices are formed and a sealing substrate are bonded together with an adhesive layer in between.

RELATED APPLICATION DATA

This application is a continuation of U.S. patent application Ser. No.15/612,718 filed Jun. 2, 2017, which is a continuation of U.S. patentapplication Ser. No. 14/560,114 filed Dec. 4, 2014, now U.S. Pat. No.9,720,448 issued Aug. 1, 2017, which is a continuation of U.S. patentapplication Ser. No. 14/299,609 filed Jun. 9, 2014 now abandoned, whichis a continuation of U.S. patent application Ser. No. 11/689,140, filedMar. 21, 2007, now U.S. Pat. No. 8,808,477 issued on Aug. 19, 2014,which is a divisional of U.S. patent application Ser. No. 10/674,255,filed Sep. 29, 2003, which is now U.S. Pat. No. 7,936,338 issued on May3, 2011, the entireties of all of which are incorporated herein byreference to the extent permitted by law. The present invention containssubject matter related to and claims priority to Japanese PatentApplication No. 2002-288803 filed in the Japanese Patent Office on Oct.1, 2002, the entirety of which also is incorporated by reference hereinto the extent permitted by law.

BACKGROUND OF THE INVENTION 1. Field of the Invention

The present invention relates to a display unit having a touch panel andits manufacturing method, and more particularly such a display unitusing organic light emitting devices and its manufacturing method.

2. Description of the Related Art

A so-called touch screen, wherein a touch panel is mounted to a displaypanel using a CRT (Cathode Ray Tube) or a liquid crystal is widely usedin banks, stations and the like. Additionally, a compact touch screen isadopted for a PDA (Personal Digital Assistant), a portable terminal andthe like.

A general touch panel used for conventional touch screens is, forexample, has a structure wherein a glass substrate and a plastic filmare layered. In such a touch panel, a glass substrate side is placedopposite to a display panel, so that a plastic film side becomes anoperation face. In the case of a liquid crystal display panel, in orderto prevent blooming phenomenon that images are distorted since theliquid crystal is transformed by getting pressure from touch paneloperations, a void is provided between a glass substrate of the touchpanel and the liquid crystal display panel.

Lately, a touch panel having a structure wherein two plastic films arelayered (hereinafter referred to as “flexible touch panel”) has beendeveloped, and this flexible touch panel is expected as what allows thePDA, the portable terminal and the like to become further thinner andlighter. However, such a flexible touch panel has no rigidity itselfsince it has no glass substrate, so that the flexible touch panel shouldbe supported by bonding a display panel thereto. Therefore, there is aproblem that the flexible touch panel cannot be provided with a voidbetween itself and the display panel as in a touch screen of aconventional liquid crystal display panel, so that it is difficult tomount the flexible touch panel to the liquid crystal display panel.

To resolve the above problem, it is thinkable that a void is secured inthe central part by fixing only four sides of the flexible touch panelon the display panel. In the case of taking such a measure for theconventional touch panel, when the plastic film is distorted or bent dueto contact with a finger or a pen, distortion or bending can berestrained or recovered by the glass substrate. However, in the case oftaking such a measure for the flexible touch panel, there is a problemthat such distortion or bending cannot be restrained or recovered, andimage quality may be lowered due to distortion or bending of the plasticfilm.

Meanwhile, it is thinkable to construct a touch screen by bonding theflexible touch panel to an organic light emitting display, instead ofthe liquid crystal display. However, so far, there has been a problemthat there is no established technique by which the flexible touch panelcan be bonded to a whole face of the organic light emitting displaywithout distortion or bending of the plastic film.

Further, in a conventional organic light emitting display, a so-calledcan sealing structure is generally adopted. The can sealing structure isa structure wherein an adhesive is applied to the rim part of a rearpanel, a sealing can made of metals or glass is bonded thereto, and agetter material such as calcium is enclosed in a space between the rearpanel and the sealing can. In such an organic light emitting displayhaving the can sealing structure, there is a problem that application toa touch screen of mobile devices particularly requiring high strength isdifficult, since reducing thickness is limited and only four sides ofthe panel is fixed on the sealing can.

SUMMARY OF THE INVENTION

In light of the foregoing, it is a first object of the invention toprovide a display unit which can realize reduction of its thickness andweight by omitting a void between a touch panel and a display panel, andits manufacturing method.

It is another object of the invention to provide a display unit whichcan improve image quality by preventing distortion or bending of thetouch panel, and its manufacturing method.

A display unit according to the invention comprises a display panelincluding a substrate wherein display devices are formed; and a touchpanel which is directly bonded to the whole face of the display panelwith an adhesive layer in between, and which detects contact with afinger or a pen.

A method of manufacturing the display unit according to the inventionincludes the steps of forming the display panel including the substratewherein the display devices are formed; and directly bonding a wholeface of the touch panel which detects contact with a finger or a pen andthe display panel together with the adhesive layer in between.

In the display unit and its manufacturing method according to theinvention, the whole faces of the touch panel and the display panel aredirectly bonded together with the adhesive layer in between. Therefore,there is no void between the touch panel and the display panel, so thata thickness of the display unit is reduced.

Here, it is preferable that the display panel has a sealing substratewhich is placed opposite to a display device side of the substrate, andthe whole faces of the substrate and the sealing substrate are bondedtogether with the adhesive layer in between. By doing this, strength ofthe display panel becomes high, leading to obtaining a display unitsuitable for mobile devices, wherein a touch screen is essential andwhich requires high strength.

A suitable touch panel is, for example, a touch panel having a structurewherein two plastic films in which respective transparent electrodes areformed are layered so that the transparent electrodes are placedopposite to each other. The reason of it is that thickness and weight ofthe display unit is further reduced. Another reason of it is that evenwhen the touch panel is such a touch panel with low rigidity, the touchpanel is supported by the display panel, so that when distortion orbending is generated in the plastic film due to contact with a finger ora pen, such distortion or bending is restrained or recovered by thedisplay panel.

Further, a suitable display device is an organic light emitting device,which has an organic layer including a light emitting layer between afirst electrode and a second electrode, and which extracts lightsgenerated in the light emitting layer from the second electrode side. Inthe structure of the invention, the touch panel and the display panelare directly bonded without providing a void between the touch panel andthe display panel since the organic light emitting device has noblooming phenomenon as in the liquid crystal. Therefore, by thestructure of the invention, high image quality can be realized.

Other and further objects, features and advantages of the invention willappear more fully from the following description.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross sectional view showing a construction of a displayunit according to a first embodiment of the invention;

FIG. 2 is an enlarged cross sectional view showing a construction of anorganic layer in organic light emitting devices illustrated in FIG. 1;

FIG. 3 is an enlarged cross sectional view showing a construction of anorganic layer in an organic light emitting device illustrated in FIG. 1;

FIGS. 4A and 4B are cross sectional views showing a method ofmanufacturing the display unit illustrated in FIG. 1 in the order ofprocesses;

FIG. 5 is a cross sectional view showing a process following FIGS. 4Aand 4B;

FIGS. 6A and 6B are explanation drawings showing a process followingFIG. 5;

FIGS. 7A to 7C are explanation drawings showing a method ofmanufacturing a display unit according to a modification of theinvention;

FIG. 8 is a cross sectional view showing a construction of a displayunit according to a second embodiment of the invention; and

FIGS. 9A and 9B are explanation drawings showing a method ofmanufacturing the display unit according to the modification of theinvention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Embodiments of the invention will be described in detail hereinbelowwith reference to the drawings.

First Embodiment

FIG. 1 shows a cross sectional structure of a display unit according toa first embodiment of the invention. This display unit is used as anultrathin organic light emitting color display unit or the like, and,for example, a touch panel 20 is bonded to a whole face of a displaypanel 10 by an adhesive layer 30.

In the display panel 10, for example, a driving panel 40 and a sealingpanel 50 are placed opposite, and whole faces of both the panels 40 and50 are bonded by an adhesive layer 60.

The driving panel 40 has a structure wherein, for example, an organiclight emitting device 10R which emits red lights, an organic lightemitting device 10G which emits green lights, and an organic lightemitting device 10B which emits blue lights are provided in order in amatrix state as a whole, on a driving substrate 11 made of an insulatingmaterial such as glass. In addition, the driving substrate 11 isprovided with a protective film (passivation film) 11A to preventmoisture and the like from intruding into the organic light emittingdevices 10R, 10G, and 10B.

In the organic light emitting devices 10R, 10G, and 10B, for example, afirst electrode 12 as an anode, an organic layer 13, and a secondelectrode 14 as a cathode are layered in this order from the drivingsubstrate 11 side. On the second electrode 14, the protective film 11Ais formed.

The first electrode 12 also has a function as a reflection layer, and itis desirable that the first electrode 12 has a reflectance as high aspossible in order to improve light emitting efficiency. For example,materials to make the first electrode 12 include simple substances oralloys of metal elements with high work function, such as platinum (Pt),gold (Au), silver (Ag), chromium (Cr), tungsten (W) and the like. Athickness of the first electrode 12 in the layer direction (hereinaftersimply referred to as “thickness”) is preferably from 100 nm to 300 nm.As an alloy material, for example, AgPdCu alloy, whose main component issilver, and which contains palladium (Pd) of 0.3 wt % to 1 wt % andcopper (Cu) of 0.3 wt % to 1 wt % can be cited.

A construction of the organic layer 13 varies according to lightemitting colors of the organic light emitting device 10. FIG. 2 shows anenlarged view of a construction of the organic layer 13 in the organiclight emitting devices 10R and 10B. The organic layer 13 of the organiclight emitting devices 10R and 10B has a structure wherein an electronhole injection layer 13A, an electron hole transport layer 13B, a lightemitting layer 13C, an electron transport layer 13D, and an electroninjection layer 13E are layered in this order from the first electrode12 side. A function of the electron hole injection layer 13A and theelectron hole transport layer 13B is to improve efficiency to injectelectron holes into the light emitting layer 13C. A function of thelight emitting layer 13C is to produce lights by current injection. Afunction of the electron transport layer 13D and the electron injectionlayer 13E is to improve efficiency to inject electrons into the lightemitting layer 13C.

The electron hole injection layer 13A of the organic light emittingdevice 10R, for example, has a thickness of about 30 nm, and made of 4,4′, 4″-tris (3-methylphenyl phenyl amino) tri-phenyl amine (MTDATA). Theelectron hole transport layer 13B of the organic light emitting device10R, for example, has a thickness of about 30 nm, and made of bis[(N-naphthyl)-N-phenyl]benzidine (α-NPD). The light emitting layer 13Cof the organic light emitting device 10R, for example, has a thicknessof about 50 nm, and made of 2,5-bis[4N-[(4-methoxyphenyl)-N-phenylamino]] stilbenzene-1,4-dica-bonitrile(BSB). The electron transport layer 13D of the organic light emittingdevice 10R, for example, has a thickness of about 30 nm, and made of8-quinolinol aluminum complex (Alq). The electron injection layer 13E ofthe organic light emitting device 10R, for example, has a thickness of 1nm, and made of lithium fluoride (LiF).

The electron hole injection layer 13A of the organic light emittingdevice 10B, for example, has a thickness of about 30 nm, and made ofMTDATA. The electron hole transport layer 13B of the organic lightemitting device 10B, for example, has a thickness of about 30 nm, andmade of α-NPD. The light emitting layer 13C of the organic lightemitting device 10B, for example, has a thickness of about 30 nm, andmade of spiro 6 Φ. The electron transport layer 13D of the organic lightemitting device 10B, for example, has a thickness of about 30 nm, andmade of Alq. The electron injection layer 13E of the organic lightemitting device 10B, for example, has a thickness of about 1 nm, andmade of lithium fluoride (LiF).

FIG. 3 shows an enlarged view of a construction of the organic layer 13in the organic light emitting device 10G. The organic layer 13 of theorganic light emitting device 10G has a structure wherein the electronhole injection layer 13A, the electron hole transport layer 13B, thelight emitting layer 13C, and the electron injection layer 13E arelayered in this order from the first electrode 12 side. The lightemitting layer 13C also has a function as an electron transport layer.

The electron hole injection layer 13A of the organic light emittingdevice 10G, for example, has a thickness of about 30 nm, and made ofMTDATA. The electron hole transport layer 13B of the organic lightemitting device 10G, for example, has a thickness of about 30 nm, andmade of α-NPD. The light emitting layer 13C of the organic lightemitting device 10G, for example, has a thickness of about 60 nm, andmade of Alq. The electron injection layer 13E of the organic lightemitting device 10G, for example, has a thickness of about 1 nm, andmade of lithium fluoride (LiF).

The second electrode 14 shown in FIGS. 1 to 3, for example, has athickness of 1 nm to 50 nm, and made of a simple substance or an alloyof metal elements with low work function, such as aluminum (Al),magnesium (Mg), calcium (Ca), sodium (Na) and the like. Specially, analloy made of magnesium and silver (MgAg alloy) is preferable, and amass ratio of magnesium and silver is preferably Mg:Ag=5:1 to 20:1.

The second electrode 14 also has a function as a semi-transparentreflection layer. Namely, these organic light emitting devices 10R, 10G,and 10B have a resonator structure wherein lights generated in the lightemitting layer 13C are resonated and extract from a second end P2, byregarding an end face of the first electrode 12 on the light emittinglayer 13C side as a first end P1, an end face of the second electrode 14on the light emitting layer 13C side as the second end P2, and theorganic layer 13 as a resonance part. Such a resonator structure ispreferable, since the lights generated in the light emitting layer 13Cgenerate multiple interference, and act as a kind of narrow band filter,so that half bandwidth of spectrum of the extracted light is reduced,and color purity can be improved. Further, such a resonator structure ispreferable, since outside lights entering from the sealing panel 50 canbe attenuated by the multiple interference as well, and reflectance ofoutside lights in the organic light emitting devices 10R, 10G, and 10Bcan be lowered extremely in combination with a color filter 52 describedlater (refer to FIG. 1).

To obtain the above effects, it is preferable that an optical distance Lbetween the first end P1 and the second end P2 of the resonatorsatisfies Mathematical Expression 1, and a resonance wave length of theresonator (peak wave length of the spectrum of the extracted light)corresponds to a peak wave length of spectrum of the light to beextracted. Actually, it is preferable that the optical distance L isselected so that L becomes a positive minimum value which satisfies theMathematical Expression 1.(2L)/λ+Φ/(2π)=m  [Mathematical Expression 1]

(In the mathematical expression, L represents an optical distancebetween the first end P1 and the second end P2, Φ represents a phaseshift (rad) of the reflection light generated in the first end P1 andthe second end P2,λ represents a peak wave length of spectrum of thelight to be extracted from the second end P2 side, and m represents awhole number which makes L be a positive number. In the MathematicalExpression 1, L and λ should share a common unit such as (nm).)

The sealing panel 50 shown in FIG. 1 has a sealing substrate 51 whichseals the organic light emitting devices 10R, 10G, and 10B along withthe adhesive layer 60. The sealing substrate 51 is made of a materialsuch as glass which is transparent to the lights generated in theorganic light emitting devices 10R, 10G, and 10B. The sealing substrate51 is, for example, provided with the color filter 52, extracts thelights generated in the organic light emitting devices 10R, 10G, and10B, absorbs outside lights reflected in the organic light emittingdevices 10R, 10G, and 10B and the wiring between them, and improves thecontrast.

The color filter 52 can be arranged on either face of the sealingsubstrate 51. However, it is preferable to arrange the color filter 52on the driving panel 40 side. The reason of it is that the color filter52 is not exposed on the surface and a structure whereinantiweatherability of the color filter 52 is considered can be obtained.Another reason of it is that when bonding the display panel 10 and thetouch panel 20, problems such as unevenness in the touch panel 20 can beprevented. The color filter 52 has a red color filter 52R, a greenfilter 52G, and a blue filter 52B, which are positioned corresponding tothe organic light emitting devices 10R, 10G, and 10B in this order.

The red color filter 52R, the green filter 52G, and the blue filter 52Bare, for example, respectively formed in the shape of rectangle with nospace between them. The red color filter 52R, the green filter 52G, andthe blue filter 52B are respectively made of a resin mixed withpigments, and adjusted so that light transmission in the targeted wavelength band of red, green or blue becomes high and light transmission inother wave length band becomes low by selecting a pigment.

Further, a wave length range with high light transmittance in the colorfilter 52 corresponds to a peak wave length λ of spectrum of the lightextracted from the resonator structure. Therefore, out of outside lightsentering from the sealing panel 50, only the light having a wave lengthequal to the peak wave length λ of spectrum of the light to be extractedfilters out through the color filter 52, and other outside lights havingother wave lengths are prevented from intruding into the organic lightemitting devices 10R, 10G, and 10B.

The protective film 11A shown in FIG. 1 is made of, for example, siliconoxide (SiO₂), silicon nitride (SiN_(x)) and the like. A function of theprotective film 11A is to prevent oxygen, moisture and the like fromintruding into the organic light emitting devices 10R, 10G, and 10B.

The touch panel 20 shown in FIG. 1 is a flexible touch panel which has astructure, for example, wherein a lower plastic film 21 and a touch-sideplastic film 22 are layered with an unshown spacer in between, andlocated on the sealing substrate 51 on the side opposite to the drivingsubstrate 11. In order to detect contact to the touch-side plastic film22 by a finger, a pen or the like, in this touch panel 20, for example,the lower plastic film 21 is provided with a transparent electrode 21A,and the touch-side plastic film 22 is provided with a transparentelectrode 22A. The lower plastic film 21 and the touch-side plastic film22 are layered so that the transparent electrodes 21A and 22A are placedopposite. The transparent electrodes 21A and 22A are connected to anunshown control system through an unshown flexible connector and thelike.

This display unit can be, for example, produced as follows.

FIGS. 4A and 4B to 6A and 6B show a method of manufacturing this displayunit in the order of processes. First, as shown in FIG. 4A, on thedriving substrate 11 made of the above-mentioned material, the firstelectrode 12 made of the above-mentioned material is deposited in theforegoing thickness by, for example, DC sputtering, selective etching ismade by using, for example, lithography technique, and patterning ismade in the form of a given shape. After that, as shown in FIG. 4A, theelectron hole injection layer 13A, the electron hole transport layer13B, the light emitting layer 13C, the electron transport layer 13D, theelectron injection layer 13E, and the second electrode 14 which have theforegoing thicknesses and are made of the foregoing materials, aresequentially deposited, for example, by deposition method, and theorganic light emitting devices 10R, 10G, and 10B as shown in FIGS. 2 and3 are formed. After that, as shown in FIG. 4A as well, the protectivefilm 11A made of the above-mentioned material is formed to cover theorganic light emitting devices 10R, 10G, and 10B of the drivingsubstrate 11. Consequently, the driving panel 40 is formed.

As shown in FIG. 4B, the red filter 52R is formed by, for example, onthe sealing substrate 51 made of the foregoing material, a material forthe red filter 52R is applied by spin coat method, and burning is madewith patterning by photolithography. Subsequently, as shown in FIG. 4Bas well, the blue filter 52B and the green filter 52G are sequentiallyformed in the same manner as in the red filter 52R. Consequently, thesealing panel 50 is formed.

Subsequently, as shown in FIG. 5, the adhesive layer 60 is formed on theprotective film 11A, the sealing substrate 51 wherein the color film 52is formed is placed opposite to the side of the organic light emittingdevices 10R, 10G, and 10B of the driving substrate 11, and whole facesof the sealing substrate 51 and the driving substrate 11 are bonded withthe adhesive layer 60 in between. Then, it is preferable that a side ofthe sealing panel 50 where the color filter 52 is formed is placedopposite to the driving panel 40. Consequently, the display panel 10 isformed.

After that, as shown in FIGS. 6A and 6B, the adhesive layer 30 is formedon the display panel 10, and the whole faces of the touch panel 20 andthe display panel 10 are bonded with the adhesive layer 30 in between.Then, first, as shown in FIG. 6A, the touch panel 20 is attached to atouch panel holding plate 70, and a roller 80 is applied onto one sideof the touch panel 20. Subsequently, as shown in FIG. 6B, the touchpanel 20 and the display panel 10 are bonded by pressure force generatedby rotational movement of the roller 80. Then, the touch panel 20 isslid on the touch panel holding plate 70 by moving the touch panelholding plate 70 in the direction of arrow A in sync with the roller 80.Consequently, the touch panel 20 and the display panel 10 can be bondedtogether without mixing air bubbles into the adhesive layer 30. Asabove, the display unit shown in FIGS. 1 to 3 is completed.

In this display unit, when a given voltage is applied between the firstelectrode 12 and the second electrode 14, current is injected into thelight emitting layer 13C, and an electron hole and an electronrecombines, leading to light emitting mainly at the interface of thelight emitting layer 13C. This light multiple-reflects between the firstelectrode 12 and the second electrode 14, and extracted through thesecond electrode 14, the protective film 11A, the color filter 52, thesealing substrate 51, and the touch panel 20. When a finger or a pencontacts the touch-side plastic film 22, the touch panel 20 detects thecontact. Then, in this embodiment, since the whole faces of the touchpanel 20 and the display panel 10 are directly bonded together with theadhesive layer 30 in between so that the touch panel 20 is supported bythe display panel 10, even when a finger or a pen contacts the touchpanel 20, no distortion or bending is generated in the touch panel 20,and image quality is improved.

As above, according to this embodiment, since the whole faces of thetouch panel 20 and the display panel 10 are directly bonded with theadhesive layer 30 in between, a void between the touch panel 20 and thedisplay panel 10 is omitted, and a thickness of the display unit can bereduced.

In particular, since the display panel 10 has a structure wherein thewhole faces of the driving substrate 11 and the sealing substrate 51 arebonded together with the adhesive layer 60 in between, strength of thedisplay panel 10 is raised. Therefore, this display unit is verysuitable as a display unit for mobile devices wherein a touch screen isessential and which require high strength.

Further, the touch panel 20 is a flexible touch panel having thestructure, wherein the lower plastic film 21 formed with the transparentelectrode 21A and the touch-side plastic film 22 formed with thetransparent electrode 22A are layered so that the transparent electrodes21A and 22A are placed opposite. Therefore, thickness and weight of thedisplay unit can be further reduced. Further, even if the touch panel 20is such a touch panel with low rigidity, since the touch panel 20 issupported by the display panel 10, when distortion or bending isgenerated in the touch-side plastic film 22 and the like due to contactwith a finger or a pen, such distortion or bending can be restrained orrecovered by the display panel 10.

In addition, particularly, since when the touch panel 20 and the displaypanel 10 are bonded together with the adhesive layer 30 in between, theroller 80 is applied onto one side of the touch panel 20 and pressureforce is applied by rotating and moving the roller 80, the touch panel20 and the display panel 10 can be bonded without mixing air bubblesinto the adhesive layer 30. Consequently, deterioration of the organiclight emitting devices 10R, 10G, and 10B due to oxygen or moisture ofair bubbles can be prevented, and the image quality can be improved.

[Modification]

FIGS. 7A and 7B show modification of the method of manufacturing thedisplay unit according to the first embodiment. In this modification,the touch panel 20 is previously incurved by setting the face bonded tothe adhesive layer 30 to outside, and pressed by the roller 80 from theother face.

First, in the same manner as in what shown in FIGS. 4A, 4B and 5 in thefirst embodiment, the display panel 10 is formed. Subsequently, as shownin FIG. 7A, the touch panel 20 is previously incurved in the shape of,for example, approximate U, by setting the lower plastic film 21 bondedto the adhesive layer 30 to outside and by using a roll (not shown) andthe like.

Next, as shown in FIG. 7B, the adhesive layer 30 is formed on thedisplay panel 10, one end 20A of the touch panel 20 which is previouslyincurved in the shape of U is placed on the display panel 10, and theroller 80 is applied to the one end 20A. Then, the roller 80 is appliedto the touch-side plastic film 22 of the touch panel 20.

Subsequently, as shown in FIG. 7C, the touch panel 20 and the displaypanel 10 are bonded together by pressing the touch panel 20 by theroller 80 from the touch-side plastic film 22 side by rolling and movingthe roller 80. In this way, force is applied in the direction of tensionto make the touch-side plastic film 22 flat. Therefore, in bonding andoperation, no distortion or bending is generated in the touch-sideplastic film 22. As above, the display unit shown in FIGS. 1 to 3 iscompleted.

As above, in this modification, since the touch panel 20 is previouslyincurved by setting the lower plastic film 21 bonded to the adhesivelayer 30 to outside, and the touch panel 20 and the display panel 10 arebonded by pressing the touch panel 20 by the roller 80 from thetouch-side plastic film 22 side, force is applied in the direction oftension to make the touch-side plastic film 22 of the touch panel 20flat. Therefore, in bonding and operation, no distortion or bending isgenerated in the touch-side plastic film 22, and image quality isimproved.

Second Embodiment

FIG. 8 shows a cross sectional structure of a display unit according toa second embodiment of the invention. This display unit is identicalwith the display unit described in the first embodiment except that thedisplay panel 10 is not provided with the sealing panel 50 and theadhesive layer 60, but is comprised of only the driving panel 40.Therefore, the same components are applied with the same symbols, andtheir detailed explanations are omitted.

The touch panel 20 is bonded on the whole face on the side where theorganic light emitting devices 10R, 10G, and 10B of the drivingsubstrate 11 are formed with the adhesive layer 30 in between. The lightemitting devices 10R, 10G, and 10B are sealed by the touch panel 20.Therefore, since the sealing panel 50 (refer to FIG. 1) and the adhesivelayer 60 are omitted, thickness and weight of the display unit can befurther reduced. Additionally, since the organic light emitting devices10R, 10G, and 10B are surely sealed by the protective film 11A, theadhesive layer 30, and the touch panel 20, deterioration due tointrusion of moisture or oxygen can be prevented.

A method of manufacturing the display unit in this embodiment is similarto that in the first embodiment except that the touch panel 20 and thedisplay panel 10 are bonded together by forming the adhesive layer 30 onthe protective film 11A. Its function is similar to that in the firstembodiment.

As above, in this embodiment, since the sealing panel 50 is notprovided, and the organic light emitting devices 10R, 10G, and 10B aresealed by the touch panel 20, thickness and weight of the display unitcan be further reduced. Additionally, since the organic light emittingdevices 10R, 10G, and 10B are surely sealed by the protective film 11A,the adhesive layer 30, and the touch panel 20, deterioration due tointrusion of moisture or oxygen can be prevented.

While the invention has been described with reference to theembodiments, the invention is not limited to the foregoing embodiments,and various modifications may be made. For example, materials,thickness, deposition methods, and deposition conditions for respectivelayers are not limited to those described in the foregoing embodiments,and other materials, thickness, deposition methods, and depositionconditions can be applied.

For example, in the foregoing first embodiment, the touch panel 20 isattached to the touch panel holding plate 70. However, it is possiblethat, as shown in FIGS. 9A and 9B, instead of the touch panel holdingplate 70, the touch panel 20 is attached to a mesh 92 which is stretchedbetween frames 91, and pressed by the roller 80 through the mesh 92.This method is preferable since an angle of bend of the touch panel 20is small so that a load to the touch panel 20 becomes small.

Further, in the foregoing second embodiment, the case using the touchpanel 20 having the structure wherein the lower plastic film 21 and thetouch-side plastic film 22 are layered has been described. However, inthe case where the sealing panel 50 is omitted as above, theconventional touch panel using a glass substrate instead of the lowerplastic film 21 can be used in order to improve strength of the displayunit.

Further, the foregoing modification can be applied not only to the firstembodiment, but also to the second embodiment. It is hereby possible torealize a more thinner and lighter display unit.

Further, for example, for the touch panel 20, various driving methodscan be used, such as resistance film method, capacitance method, opticalmethod, ultrasonic method, and electromagnetic induction method.

Further, for example, regarding a structure of the organic lightemitting devices 10R, 10G, and 10B, their layer order can be opposite tothat in the foregoing embodiments in such a way that the secondelectrode 14, the organic layer 13, and the first electrode 12 arelayered on the driving substrate 11 in this order from the drivingsubstrate 11, and lights can be extracted from the driving substrate 11side. In this case, the touch panel 20 is placed on the drivingsubstrate 11 on the side opposite to the organic light emitting devices10R, 10G, and 10B.

Further, for example, in the foregoing embodiments, the case using thefirst electrode 12 as an anode and the second electrode 14 as a cathodehas been described. However, it is possible that anode and cathode arereversed in such a way that the first electrode 12 is a cathode and thesecond electrode 14 is an anode. Further, it is possible, along withusing the first electrode 12 as a cathode and the second electrode 14 asan anode, the second electrode 14, the organic layer 13, and the firstelectrode 12 are layered on the driving substrate 11 in this order fromthe driving substrate 11 side, and the lights are extracted from thedriving substrate 11 side.

Further, in the foregoing embodiments, the structures of the organiclight emitting devices have been specifically described. However, alllayers are not necessarily provided, and other layer can be furtherprovided. For example, it is possible that the first electrode 12 has atwo-layer structure wherein a transparent conductive film is layered onthe top of a reflection film such as a dielectric multi-layer film orAl. In this case, an end face of the reflection film on the lightemitting layer side composes an end of the resonation part, and thetransparent conductive film composes a part of the resonation part.

Further, in the foregoing embodiments, the case wherein the secondelectrode 14 is comprised of the semi-transparent reflection layer hasbeen described. However, it is possible that the second electrode 14 hasa structure wherein the semi-transparent reflection layer and atransparent electrode are layered from the first electrode 12 side. Afunction of this transparent electrode is to lower electric resistanceof the semi-transparent reflection layer. This transparent electrode ismade of a conductive material having a sufficient translucency to thelights generated in the light emitting layer. As a material to make thetransparent electrode, for example, ITO or a compound containing indium,zinc (Zn), and oxygen is preferable, since good conductivity can beobtained by using these materials even if deposition is made at roomtemperature. A thickness of the transparent electrode can be, forexample, 30 nm to 1,000 nm.

Further, in the foregoing embodiments, the case wherein the organiclight emitting devices 10R, 10G, and 10B are formed on the drivingsubstrate 11 has been described. However, this invention can be appliedto a display wherein other display devices such as an inorganicelectroluminescence device is formed on the driving substrate 11, FED(Field Emission Display), or a paper-like display which has been notedlately.

As described above, according to the display unit of the invention orthe method of manufacturing the display unit of the invention, since thewhole faces of the touch panel and the display panel are directly bondedtogether with the adhesive layer in between, a void between the touchpanel and the display panel can be omitted and a thickness of thedisplay unit can be reduced.

According to the display unit of one aspect of the invention or themethod of manufacturing the display unit of one aspect of the invention,since the display panel has the sealing substrate which is placedopposite to the display device side of the substrate, and the wholefaces of the substrate and the sealing substrate are bonded togetherwith the adhesive layer in between, strength of the display panel isimproved. Therefore, this display unit is extremely suitable as adisplay unit for mobile devices wherein a touch screen is essential andwhich require high strength.

According to the display unit of another aspect of the invention or themethod of manufacturing the display unit of another aspect of theinvention, since the touch panel has a structure wherein two plasticfilms wherein respective transparent electrodes are formed are layeredso that these transparent electrodes are placed opposite to each other,thickness and weight of the display unit is further reduced. Inaddition, even if the touch panel is such a touch panel with lowrigidity, the touch panel is supported by the display panel. Thus, whendistortion or bending is generated in the plastic film due to contactwith a finger or a pen, such distortion or bending is restrained orrecovered by the display panel.

According to the display unit of still another aspect of the inventionor the method of manufacturing the display unit of still another aspectof the invention, since the touch panel is provided on the side wherethe display devices of the substrate are formed, and the display devicesare sealed by the touch panel, thickness and weight of the display unitcan be further reduced. In addition, since the display devices aresurely sealed by the adhesive layer and the touch panel, deteriorationcan be prevented.

According to the method of manufacturing the display unit of stillanother aspect of the invention, since when the touch panel and thedisplay panel are bonded together with the adhesive layer in between,one side of the touch panel is applied to the roller, and pressure forceis applied by rotational movement of the roller, the touch panel and thedisplay panel can be bonded together without mixing air bubbles into theadhesive layer. Therefore, deterioration of the display devices due tooxygen or moisture of air bubbles can be prevented, and image qualitycan be improved.

According to the method of manufacturing the display unit of stillanother aspect of the invention, since when the touch panel is pressedby the roller, the touch panel is previously incurved by setting theface bonded to the adhesive layer to outside, and the touch panel ispressed by the roller from the other face, i.e. the side to whichcontact by a finger or a pen is made, force is applied in the directionof tension to make the face to which contact by a finger or a pen ismade flat. Therefore, in bonding, no distortion or bending is generatedin the face to which contact by a finger or a pen is made, and imagequality is improved.

Obviously many modifications and variations of the present invention arepossible in the light of the above teachings. It is therefore to beunderstood that within the scope of the appended claims the inventionmay be practiced otherwise than as specifically described.

What is claimed is:
 1. A display unit, comprising: a display panelcomprising (a) a display panel substrate, (b) organic light emittingdevices on the display panel substrate, and (c) a protective filmdirectly on and around the organic light emitting devices, theprotective film sealing the organic light emitting devices; a flexibletouch sensing panel that can detect contact thereon by a suitablecontact element and comprising a plastic film; a sealing panelcomprising a sealing substrate; a first adhesive layer securing theflexible touch sensing panel to the sealing panel; and a second adhesivelayer securing the sealing panel to the display panel, wherein, theprotective film comprises silicon oxide, silicon nitride, or both and isconfigured to prevent intrusion of moisture or oxygen, the firstadhesive layer extends across a first whole face of the sealing paneland directly contacts both the sealing panel and the flexible touchsensing panel, the second adhesive layer extends across and directlycontacts the protective film and a second face of the sealing panel, theorganic light emitting devices are configured to emit light through thetouch sensing panel, and at least one of the organic light emittingdevices has a resonator structure and includes (i) an anode electrode,(ii) a cathode electrode, and (iii) an organic light emitting layerdisposed between the anode electrode and the cathode electrode, lightgenerated in the light emitting layer being resonated between the anodeelectrode and the cathode electrode and being emitted from the anodeelectrode or the cathode electrode.
 2. The display unit of claim 1,wherein the touch sensing panel includes a transparent electrode.
 3. Thedisplay unit according to claim 2, wherein the touch sensing panelincludes a second plastic film which carries a second transparentelectrode.
 4. The display unit of claim 1, wherein each organic lightemitting device is an organic light emitting diode with an anodeelectrode having a thickness from 100 nm to 300 nm, both inclusive. 5.The display unit of claim 4, wherein each organic light emitting diodehas a cathode electrode with a thickness from 1 nm to 50 nm, bothinclusive.
 6. The display unit of claim 1, wherein: the anode electrodeincludes silver; and the cathode electrode includes an alloy made ofmagnesium and silver.
 7. The display unit of claim 1, wherein the touchsensing panel plastic film carries a transparent electrode.
 8. Thedisplay unit of claim 1, wherein the protective layer is made of siliconoxide.
 9. The display unit of claim 1, wherein the protective layer ismade of silicon nitride.
 10. The display unit of claim 1, wherein one ofthe anode electrode or the cathode is a reflective layer and the otherof the anode electrode or the cathode electrode is a semitransparentlayer.
 11. A display unit, comprising: a display panel comprising (a) adisplay panel substrate, (b) organic light emitting devices on thedisplay panel substrate, and (c) a protective film directly on andaround the organic light emitting devices and sealing the plurality oforganic light emitting devices; a flexible touch sensing panel that candetect contact thereon by a suitable contact element and comprising aplastic film; and an adhesive layer securing the flexible touch sensingpanel to the display panel, wherein, the light emitting devices aresealed by the protective film, the protective film provides a planarsurface across a whole face of the display panel, the protective filmcomprises silicon oxide, silicon nitride, or both and is configured toprevent intrusion of moisture and oxygen, the adhesive layer extendsacross and directly contacts the planar surface of the protective filmand a face of the flexible touch sensing panel, the plurality of organiclight emitting devices are configured to emit light through the touchsensing panel, and at least one of the display devices has a resonatorstructure and includes (i) an anode electrode, (ii) a cathode electrode,and (iii) an organic light emitting layer disposed between the anodeelectrode and the cathode electrode, light generated in the lightemitting layer being resonated between the anode electrode and thecathode electrode and being emitted from the anode electrode or thecathode electrode.
 12. The display unit of claim 11, wherein the touchsensing panel includes a transparent electrode.
 13. The display unitaccording to claim 12, wherein the touch sensing panel includes a secondplastic film which carries a second transparent electrode.
 14. Thedisplay unit of claim 11, wherein each organic light emitting device isan organic light emitting diode with an anode electrode having athickness from 100 nm to 300 nm, both inclusive.
 15. The display unit ofclaim 14, wherein each organic light emitting diode has a cathodeelectrode with a thickness from 1 nm to 50 nm, both inclusive.
 16. Thedisplay unit according to claim 14, wherein the touch sensing panelplastic film carries a transparent electrode.
 17. The display unit ofclaim 11, wherein: the anode electrode includes silver; and the cathodeelectrode includes an alloy made of magnesium and silver.
 18. Thedisplay unit of claim 11, wherein the protective layer is made ofsilicon oxide.
 19. The display unit of claim 11, wherein the protectivelayer is made of silicon nitride.
 20. The display unit of claim 11,wherein one of the anode electrode or the cathode is a reflective layerand the other of the anode electrode or the cathode electrode is asemitransparent layer.